Mediterranean Diet and Time-Restricted Feeding in Ulcerative Colitis Remission

Ulcerative colitis (UC) is a chronic inflammatory bowel disease characterized by periods of remission and relapse, associated with alterations in the gut microbiota, immune dysregulation, and impaired intestinal barrier function. Current treatments focus on controlling inflammation; however, there is a growing interest in non-pharmacological strategies, including dietary interventions, to improve disease outcomes and quality of life.

The Mediterranean diet has been associated with anti-inflammatory effects, improved gut microbiota composition, and increased production of short-chain fatty acids (SCFAs), which play a key role in maintaining intestinal homeostasis. Time-restricted feeding (TRF), a form of intermittent fasting that limits daily food intake to a specific time window, has shown potential metabolic and anti-inflammatory benefits in preclinical and human studies. However, evidence on the combined effects of these interventions in patients with UC is limited.

This study is a pilot randomized controlled trial designed to evaluate the effects of a 12-week intervention with a Mediterranean diet alone or in combination with TRF on gut health, inflammation, and quality of life in patients with UC in remission.

A total of 45 participants will be randomized in a 1:1:1 ratio into three groups: (1) Mediterranean diet, (2) Mediterranean diet combined with TRF (16-hour fasting and 8-hour eating window), and (3) standard dietary advice (control group). Nutritional plans will be individualized and isocaloric.

Participants will be assessed at baseline, week 6, and week 12. The primary outcome is the change in fecal SCFA levels, measured using gas chromatography. Secondary outcomes include changes in fecal calprotectin, C-reactive protein, gastrointestinal symptoms, and quality of life assessed by validated questionnaires.

This study aims to generate preliminary evidence on the effectiveness and feasibility of combined dietary interventions in UC, supporting future larger-scale clinical trials.

Inclusion criteria

• Adults aged 18 to 60 years
• Diagnosis of ulcerative colitis
• Clinical remission for at least 6 months
• Fecal calprotectin < 250 µg/g in the last 3 months
• Daily eating window ≥ 11 hours

Exclusion criteria

• Active ulcerative colitis
• History of gastrointestinal surgery
• Liver or kidney disease
• Pregnancy
• Eating disorders
• Use of supplements (protein, antioxidants, probiotics)
• Current restrictive diets (vegetarian, vegan, gluten-free, low-FODMAP)
• High levels of physical activity